| 摘要 |
1,270,584. Coated products. LITTON BUSINESS SYSTEMS Inc. and BECTON DICKINSON & CO. 14 July, 1969 [16 July, 1968], No. 35408/69. Heading B2E. [Also in Divisions B8 and D2] A sheet of material is coated on one surface with a thermosetting resin not more than 90% cured and having -CH 2 OH groups capable of releasing free formaldehyde on heating and/or aging. The amount of free hydrogen ions or hydroxyl ions available for creating an acidic or basic atmosphere in the region of the sheet is such that the sheet could be said to have a pH in the range of 4 to 9. The sheet of material may also be coated on the other surface with a vapour transmission proof coating. The coating of resins such as phenol-formaldehyde, urea-formaldehyde, and melamine-formaldehyde may be achieved by reverse roll, wire rod or air knife coating operations. The vapour transmission proof coating may comprise resins such as polyethylene, polypropylene and polyvinylidene chloride or alternatively a hot melt coating of a high molecular weight ethylenevinyl acetate copolymer combined with petroleum waxes. |
